Machine Type Communication (MTC) was introduced by the international standardization organization 3GPP initially in the release REL. 10. The working team SA2 of the 3GPP has recently approved a new Work Item (WI) on MTC of the release REL. 12, i.e., machine-type and other mobile data application communication enhancements. The invention is focused on a part of this new work item, i.e., group feature based machine type communication. A machine type communication group will be referred below as an MTC group for the sake of conciseness.
Group based messaging is defined in the prior art as follows: group based messaging can be used to distribute efficiently the same message (e.g., a trigger request) to the members in an MTC group, all of which are located in a particular geographical area upon the request of the SCS (Service Capability Server). The geographical area for distribution is a concept used in 3GPP system and can be a cell sector, a cell, a group of cells or a Public Land Mobile Network (PLMN).
As further noted in the prior art, a group message is initiated by a trusted SCS. The following information has to be included over an interface via which the SCS transmits the group message:
1) Application layer data of the group message; and
2) A group identifier corresponding to the group message.
Optionally, there is a location/area and a Radio Access Technology in which the group message has to be distributed.
Although a Cell Broadcast Service (CBS) can offer a fundamental capability to transmit a group based trigger message (noted the trigger message is one of the important group messages), some details for group message distribution have not been taken into account. For example, where and how to map an external group identifier and an internal group identifier, which CBS entities should be used to transmit a group message, etc. Moreover, there are also some drawbacks for CBS itself to act as an alternative to transmit a group based trigger message, particularly as follows:
1) In some typical MTC applications, both the capability and the behavior of an MTC device is simpler than a normal UE, and at this time CBS is inefficient;
2) Moreover, since CBS is more suitable for the transmission of a text service, CBS may not be competent when an MTC server may distribute a larger amount of data to its MTC devices; and
3) Since CBS has not been very popular for bearing services, that is, it has not been deployed widely, a group based trigger message which is a killer service of MTC may cause CBS to become deployed widely and then bring a deployment stress to operators.
As can be apparent from the analysis above, the CBS can not be competent for all the application scenarios where a group message is distributed, so it may not be practicable to perform a task of distributing a group message simply through CBS; and moreover there are several types of group messages, and a unified solution may not be practicable, either.